I really wouldn't worry about it. I'm average height at 5'3", although I was convinced whilst at school that I was rather small, as everyone I knew (male and female) was at least 5'7". That's hilarious now because at least 3 of my friends are shorter than me, especially my flat mate who is under 5'.
Just expect to be ID'd more often than most! Oh but if you look really young, some of my friends (in their 20s) were hit on by 15 year olds. Something to watch out for.